Multi-layer membrane capsule for preparing a beverage

ABSTRACT

A system, method and capsule are usable for preparing a predetermined quantity of beverage suitable for consumption using an extractable product. The system includes an exchangeable capsule, and an apparatus including a receptacle for holding the exchangeable capsule, and a fluid dispensing device for supplying a fluid to the exchangeable capsule. The exchangeable capsule includes a circumferential wall, a bottom, and a lid. The wall, bottom and lid enclose an inner space including the extractable product. The receptacle includes bottom piercing means intended for piercing an entrance area of an alternative capsule for creating at least one entrance opening for supplying the fluid to the extractable product. The entrance area of the capsule includes an entrance filter for supplying the fluid to the extractable product there through. In use, the entrance filter is positioned at a distance from the bottom piercing means, such that the capsule of the system is not pierced by the bottom piercing means. The filter is a multi-layer filter including at least a first layer and a second layer bonded together. The first layer has a higher tear strength than the second layer and the second layer has a higher stiffness than the first layer.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/327,010, filed Dec. 15, 2011, which is a continuation ofInternational Patent Application No. PCT/NL2009/050832, filed Dec. 30,2009, which claims priority to European Patent Application Nos.09162917.0, filed June.17, 2009; 09162941.0, filed Jun. 17, 2009;09162927.9, filed Jun. 17, 2009; and 09162984.0, filed Jun. 17, 2009.All of these applications are hereby incorporated herein by reference.

BACKGROUND

The invention relates to a system for preparing a predetermined quantityof beverage suitable for consumption using an extractable product,comprising an exchangeable capsule, and an apparatus comprising areceptacle for holding the exchangeable capsule, and a fluid dispensingdevice for supplying an amount of a fluid, such as water, under pressureto the exchangeable capsule, wherein the exchangeable capsule comprisesa circumferential wall, a bottom and a lid enclosing an inner spacecomprising the extractable product, wherein the bottom comprises anentrance area and the system is arranged for bringing the fluiddispensing device in fluid connection with the entrance area forsupplying the fluid to the extractable product for preparing thebeverage, and wherein the lid comprises an exit area and the systemcomprises an outlet which, in use, is in fluid communication with theexit area for draining the prepared beverage from the capsule andsupplying the beverage to a container such as a cup.

Such a system using a capsule enclosing an inner space comprising theextractable product is known per se. The exit area of the lid may beprovided with a filter sheet or other perforate and/or porous filter.The capsule may for example comprise roasted and ground coffee asextractable product. The capsule may be used for preparing apredetermined quantity of coffee in a suitable apparatus. A drawback ofsuch a capsule may be that the reproducibility of the prepared beveragemay be poor. Due to for example poor stability, deformation, rupture,tearing and/or widening of e.g. openings of the filter under influenceof e.g. fluid pressure in the capsule, the quality of the preparedbeverage may be poor and/or the quality of the prepared beverage may notbe reproducible and/or may vary from capsule to capsule.

SUMMARY

It is an object of the invention to improve the above system, and morespecifically to improve the reproducibility of the quality of theprepared beverage.

Thereto, according to the invention, a system is provided for preparinga predetermined quantity of beverage suitable for consumption using anextractable product, comprising an exchangeable capsule, and anapparatus comprising a fluid dispensing device for supplying an amountof a fluid, such as water, under pressure to the exchangeable capsule,and a receptacle for holding the exchangeable capsule, wherein theexchangeable capsule comprises a circumferential wall, a bottom, and alid enclosing an inner space comprising the extractable product, whereinthe fluid dispensing device is arranged for supplying the fluid to theextractable product through the bottom for forming the beverage, whereinthe bottom comprises an entrance area and the system is arranged forbringing the fluid dispensing device in fluid connection with theentrance area for supplying the fluid to the extractable product forpreparing the beverage, wherein the lid comprises an exit area and thesystem comprises an outlet which, in use, is in fluid communication withthe exit area for draining the prepared beverage from the capsule andsupplying the beverage to a container such as a cup, wherein thereceptacle is arranged for draining the prepared beverage from thecapsule through the exit area, wherein the exit area of the capsulecomprises a sheet-shaped multi-layer filter comprising at least a firstlayer and a second layer bonded together, wherein the first layer has ahigher tear strength than the second layer and wherein the second layerhas a higher stiffness than the first layer.

By providing a multi-layer filter of which a first layer has a highertear strength than a second layer and the second layer has a higherstiffness than the first layer and wherein the first and second layersare bonded together, rupture of the filter may be avoided underinfluence of e.g. fluid pressure. The filter may comprise perforateand/or porous layers.

For example, if the filter comprises layers with openings, the firstlayer may prevent the openings from tearing and the second layer mayprevent the openings from widening under the influence of fluidpressure. For example, if the filter comprises porous layers, the firstlayer may prevent rupture of the filter, the second layer may minimizedeformation of the filter. By bonding the layers together, the layersmay strengthen each other and may thus provide a multi-layer filter ofwhich deformation and/or rupture may be minimized. Bonding the layerstogether may be done by a chemical or a physical bond. For example, thelayers may be glued together, or they may be heat-pressed to each other.Preferably, the layers are bonded together over approximately the entiresurface. For producing the filter, the layers may be bonded together,for example, the layers may be sealed together. Then a non-porous layermay be perforated for example, with a hot or cold needle or with alaser. Other ways of forming openings may also be possible, e.g.removing material chemically or mechanically, such as cutting. Also, itmay be possible to provide an ‘open’ layer and the openings may beformed by closing chemically or mechanically, e.g. gluing, sealing,painting etc. the areas around the determined openings.

The tear strength is a property of the material used for the layer andas such defined by the manufacturer of the material. The tear strengthrelevant for the invention is the tear strength of the material when alayer of the material is loaded in the plane of the layer.

The stiffness is a property of the material used for the layer and assuch defined by the manufacturer of the material. The stiffness relevantfor the invention is the stiffness of the material when a layer of thematerial is loaded transverse to the plane of the layer.

The tear strength of the first layer is thus significantly higher thanthe tear strength of the second layer and may therefore prevent ruptureof the openings of the filter. The stiffness of the second layer is thussignificantly higher than the stiffness of the first layer and maytherefore minimize deformation of the openings of the filter.

Deformation and/or rupture of the filter may lead to inferior quality ofthe prepared beverage. By avoiding deformation and/or rupture of thefilter, the quality of the prepared beverage may be approximately moreconstant from capsule to capsule. Beverage prepared with a capsuleaccording to the invention may have an improved quality and may be morereproducible from one capsule to another.

For example, there are state of the art closed filters that are intendedto be torn open during preparation of the beverage. This tearing processhowever is uncontrolled and the beverage is not reproducible from onecapsule to another because the tearing of the openings is not wellreproducible from one capsule to another. Also, grains and/or othersediments of the extractable product may come into the prepared beveragethrough the torn openings, which may reduce the quality of the preparedbeverage. By providing a multi-layer filter of which a first layer has ahigher tear strength and the second layer has a higher stiffness, thefilter layer may be designed to minimize rupture and/or deformation andto optimize reproducibility and controllability of the preparation ofthe beverage.

Preferably, the first layer has a tear strength that is at least 20%,preferably 50% higher than the tear strength of the second layer.Preferably, the second layer has a stiffness that is at least 20%,preferably 50% higher than the stiffness of the first layer to provide asufficiently stiff and strong filter.

In an embodiment, the multi-layer filter may comprise more than twolayers of which following layers have a higher tear strength and ahigher stiffness respectively. The multi-layer filter may act as a morestable flow resistance for the fluid under pressure in the capsule.

By providing the multi-layer filter with a first and a second layerbonded together, wherein the first layer has a higher tear strength thanthe second layer and the second layer has a higher stiffness than thefirst layer, a reproducible fluid pressure may be built up in thecapsule comprising a lid with such a multi-layer filter. By providing asufficiently strong and sufficiently stiff multi-layer filter,sufficient pressure may be developed in the capsule in a controlledand/or predetermined way, thus providing a better quality extractedbeverage. The layers can be perforate and/or porous, the dimensions ofthe perforations and/or the pores may remain approximately the sameunder influence of the pressure in the capsule. Preferably, thedimensions may deviate less than 3% during use of the capsule underinfluence of the pressure in the capsule. The perforations and/or thepores may not tear and any variation of the openings is predeterminedand controlled. Contrary to tearing of a filter layer, which isuncontrolled and unpredictable, the behavior of the openings of themulti-layer filter can be controlled and predetermined.

In an embodiment, the openings in the multi-layer filter may be formedby a laser. Due to the heat of the laser, on a peripheral edge of anopening a melting ridge may be provided. In the melting ridge, morematerial is present, resulting in a locally reinforced area. Thismelting ridge may also contribute to the resistance of the first layeragainst tearing and/or to the stiffness of the second layer. For thecreation of the melting ridge it is unimportant from which side thelaser focuses on the filter, because due to the different mechanicalproperties of the layers in the filter, the melting ridge will becreated on the same side.

Also, the thickness of the layers may be relatively limited. Forexample, the thickness of a layer may be between approximately 5 μm andapproximately 40 μm. Preferably, the thickness of the layers is betweenapproximately 10 μm and approximately 35 μm. For example, the thicknessof the first layer can be approximately 12 μm or approximately 23 μm,the thickness of the second layer can be approximately 30 μm. In anembodiment, the first layer having the higher tear strength may beprovided from chlorinated polypropylene (CPP) and may be approximately30 μm thick. The second layer having the higher stiffness may beprovided from polyethylene therephthalate (PET) and may be approximately15 μm thick.

In an embodiment, the first layer may be provided at the inside of thecapsule, i.e. directed towards the inner space with the extractableproduct. The grains of the extractable product may then cooperate withthe material of the first layer by slightly pressing in the material, inparticular near the openings. Thus the grain particles may cooperate tobridge the opening and thus may help to provide the flow resistance.

Preferably, the pores and/or perforations of the multi-layer filter aresmaller than the grain size of the extractable product such that theextractable product remains in the capsule. The flow restriction may beformed by the multi-layer filter itself and/or by the multi-layer filterin combination with the grains of the extractable product, e.g. whengrains partly obstruct pores and/or perforations of the filter. Theopenings can be between approximately 0.2 mm and approximately 0.4 mm.The number of openings and/or the size of the openings may be determineddepending on the grind of the coffee or extractable product. The grindof the coffee in combination with the distribution and/or number and/orsize of the openings is an aspect determining the quality of theprepared coffee. Preferably, this combination between grind anddistribution and/or number and/or size of the filter openings results incoffee with a more constant quality and/or more cream and/or morereproducibility and/or more resemblance to the classic brewed espressoand/or a higher number of dry matter in the prepared coffee.

By providing a capsule of which the first layer is of a first materialand the second layer is of a second material which layers may be bondedtogether, a relative cost effective multi-layer filter may be obtainedof which deformation and/or rupture may be avoided under influence ofe.g. fluid pressure in the capsule. For example, the first layer maycomprise polypropylene or the second layer may comprise polyethylene orvice versa. Also polyamide or any other material, such as e.g. nylon,polyethylene therephthalate (PET), chlorinated polypropylene (CPP),ethylene vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), linear lowdensity poly ethylene (L-LDPE), polypropylene (PP), low density polyethylene (LDPE), with appropriate characteristics may be used. Offcourse, many other materials may be used. Also, a first layer may befilter paper and the second layer may be a perforate foil or both layersmay be perforate foils with openings that correspond to each other.

Further, the entrance area may be formed as a filter as well. Byproviding the bottom with a multi-layer filter comprising at least twolayers bonded together of which a first layer has a higher tear strengththan a second layer and the second layer has a higher stiffness than thefirst layer, a bottom filter may be obtained that may be lesssusceptible to tear and/or rupture and/or deformation. Also, theentrance filter may be a multi-layer filter and the exit filter may be asingle layer filter or vice versa.

By providing a capsule of which the lid and the bottom comprise such amulti-layer filter a reproducible and/or controllable fluid pressure maybe developed in the capsule, thus providing a reproducible quality ofprepared beverage.

In an embodiment, the receptacle of the apparatus of the system maycomprise a support surface against which the lid of the capsule mayabut. The support surface may comprise a non-flat geometry of forexample ribs and/or grooves. For a capsule with a lid comprising amulti-layer filter according to the invention, the filter may in thecase of a non-flat geometry be sufficiently flexible and/or elastic tofollow the geometry of the support surface without tearing and/orrupture, or, if the filter comprises perforations, without substantiallywidening of the perforations. In an embodiment, the filter only followsthe tops of the non-flat geometry and may not deform until into thebottoms of the non-flat geometry. For example, if the non-flat geometrycomprises regularly arranged blunt tops and bottoms in between, thefilter may only contact the top surfaces during preparation of thebeverage under influence of the pressure in the capsule. The filter maybe sufficiently stiff not to deform until the bottom of the non-flatgeometry.

In an embodiment, the fluid may be provided to the capsule by eitherpiercing a closed bottom of the capsule, or by providing the bottom ofthe capsule with a sheet-shaped filter layer through which the fluid mayenter the capsule. The sheet-shaped multi-layer filter may then besufficiently stiff and strong as not to be pierced by the piercingmeans. Also when an apparatus for preparing the beverage comprisesbottom piercing means, the bottom of the capsule may be arranged at sucha distance of the lid of the capsule that the bottom piercing meanscannot pierce the bottom when in use.

In an embodiment, the entrance area of the bottom may be provided with amulti-layer filter for entering the fluid under pressure in the capsule.By providing the layers of the filter sufficiently strong and/orsufficiently stiff, such that the multi-layer filter may not be piercedby the bottom piercing means, the entrance filter may, in use, stayintact. Thus a stable entrance area may be provided and a reliable andreproducible pressure developed may be obtained in the capsule.

The invention also relates to a capsule with a multi-layer filter foruse in such a system.

The invention also relates to the use of a capsule for preparing apredetermined quantity of beverage in an apparatus of such a system.

The invention further relates to a method for preparing a predeterminedquantity of beverage suitable for consumption using an extractableproduct, comprising providing an exchangeable capsule, comprising acircumferential wall, a bottom, and a lid enclosing an inner spacecomprising the extractable product, providing an apparatus comprising areceptacle for holding the exchangeable capsule, a fluid dispensingdevice for supplying an amount of a fluid, such as water, under pressureto the exchangeable capsule for preparing the beverage, and an outletwhich, in use, is in fluid communication with the capsule for drainingthe prepared beverage from the capsule and supplying the beverage to acontainer such as a cup, supplying the fluid to the extractable productfor preparing the beverage, wherein the lid of the capsule is asheet-shaped multi-layer filter comprising at least a first layer and asecond layer bonded together, wherein the first layer has a higher tearstrength than the second layer and wherein the second layer has a higherstiffness than the first layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further elucidated by means of non-limitingexamples referring to a drawing in which

FIG. 1 shows an embodiment of the system according to the invention;

FIG. 2 shows a first embodiment of a capsule according to the invention,

FIG. 3 shows a second embodiment of a capsule according to theinvention; and

FIG. 4 shows a third embodiment of a capsule according to the invention

In this description, identical or corresponding items have identical orcorresponding reference numerals. The exemplary embodiments shown shouldnot be construed to be limitative in any manner and serve merely asillustration.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 shows an example of an embodiment of a system 1 according to theinvention for preparing a predetermined quantity of beverage suitablefor consumption using an extractable product. The system 1 comprises anexchangeable capsule 2, and an apparatus 104. The apparatus 104comprises a receptacle 106 for holding the exchangeable capsule 2. Inthis example, the receptacle 106 has a shape complementary to the shapeof the capsule 2. In FIG. 1 a gap is drawn between the capsule 2 and thereceptacle 106 for clarity. It will be appreciated that, in use, thecapsule 2 may lie in contact with the receptacle 106. The apparatus 104further comprises a fluid dispensing device 108 for supplying an amountof a fluid, such as water, under pressure to the exchangeable capsule 2.

In the system 1 shown in FIG. 1, the exchangeable capsule 2 comprises acircumferential wall 10, a bottom 12 closing the circumferential wall 10at a first end 14, and a lid 16 closing the circumferential wall 10 at asecond end 18 opposite the bottom 12. The circumferential wall 10, thebottom 12 and the lid 16 enclose an inner space 20 comprising theextractable product. In this example, the exchangeable capsule 2comprises an amount of extractable product suitable for preparing asingle portion of the beverage, preferably a single cup of the beverage,e.g. from 30-200 ml of the prepared beverage. The exchangeable capsule,thus, is a single-portion-pack. The extractable product may e.g. beroasted and ground coffee.

The system 1 of FIG. 1 comprises bottom piercing means 122 intended forpiercing an alternative capsule. FIG. 1 shows the bottom piercing meansin an extended position, intended for creating an entrance opening inthe bottom of an alternative capsule. According to the invention, thecapsule 2 comprises an entrance filter 34 which is positioned at adistance from the bottom piercing means 12, such that the capsule 2 isnot pierced by the bottom piercing means 122 and the bottom 12 staysintact when the bottom piercing means is brought in the extendedposition.

In FIG. 1 the piercing means 122 comprise a bore 126 through which thefluid is supplied to an inner space of the receptacle 106. The fluid,here hot water under a pressure built up to and above e.g. 6 bars, willflow through the entrance filter 34 into the inner space 20 of thecapsule 2 for extracting desired substances from the extractableproduct, in this example approximately 4-8 grams of roasted and groundcoffee, for preparing, in this example the single cup of the beverage,here coffee. The fluid may be supplied with a pressure between 4 and 20bars, preferably between 5 and 18 bars and more preferably between 6 and15 bars, for example 12 bars. Depending on the compaction, grain sizeand/or desired character of the beverage, between 4 and 10 grams ofextractable product may be contained in the capsule 2.

Thus, more in general, in the example of FIG. 1, the bottom 12 comprisesan entrance area, formed by the entrance filter 34, and the system 1 isarranged for bringing the fluid dispensing device 108 in fluidconnection with the entrance area for supplying the fluid to theextractable product for preparing the beverage.

In the example of FIG. 1, the circumferential wall 10 is substantiallyrigid. The circumferential wall may e.g. comprise a plastics materialand may be formed by e.g. injection moulding, vacuum-forming,thermoforming or the like, or may comprise a metal material. Also, inthe example of FIG. 1, the circumferential wall 10 is frusto-conical,but other shapes are also possible. For example, the circumferentialwall may be cylindrical or pyramidal.

In the example of FIG. 1 the bottom 12 is integral with thecircumferential wall 10. In this example the entrance filter 34 isformed by a plurality of entrance openings 24 in the bottom 12. In thisexample the plurality of entrance openings 24 is distributed oversubstantially the entire bottom 12. Thus, the fluid is supplied to theextractable product via the plurality of entrance openings 24, whichcauses the extractable product to be wetted over substantially theentire cross section of the capsule 2. Hence, a very homogeneous supplyof fluid to the extractable product is obtained. Also, patterns ofopenings and/or areas with openings in conjunction with areas withoutopenings may also be provided, for example the openings may be arrangedin the central area of the filter, a peripheral area of the filter maybe kept without openings.

According to an aspect of the invention, the system 1 of FIG. 1comprises lid piercing means 128 intended for piercing the lid of analternative prior art capsule when the lid sufficiently presses againstthe lid piercing means 128 under the influence of the pressure of thefluid and/or beverage in the prior art capsule for creating at least oneexit opening through which the beverage can drain from the prior artcapsule.

According to the invention, the capsule 2 comprises an exit filter 36,through which the beverage can drain from the capsule 2. According tothe invention, the exit filter 36 is a multi-layer exit filtercomprising at least a first layer and a second layer bonded together.The first layer has a higher tear strength than the second layer and thesecond layer has a higher stiffness than the first layer, preferably thefirst layer has a significantly higher tear strength than the secondlayer and the second layer has a significantly higher stiffness than thefirst layer. The exit filter 36 is thus sufficiently strong andsufficiently stiff not to be pierced by the lid piercing means 128 underthe influence of the pressure inside the capsule 2. Under influence ofthe pressure inside the capsule 2, the exit filter 36 may stay intactunder influence of the pressure, it may not tear, rupture or be piercedby the lid piercing means. Sufficient pressure may be built up in thecapsule 2 for a good quality beverage. Moreover, due to the sufficientstrong and sufficient stiff exit filter, the pressure built up may bereproducible and/or controllable from one capsule to another, therebyimproving the reproducibility and/or quality of the brewed beverage.

Alternatively, or additionally, the exit filter 36 forms a sufficientflow resistance for the beverage exiting the capsule 2, that the exitfilter 36 is not pressed against the lid piercing means 128 withsufficient force to be pierced by the lid piercing means 128 and the lid16 stays intact. The exit filter 36 may be pressed against the lidpiercing means, but will not tear or rupture. The exit filter 36 issufficiently stiff and strong that it may follow only the top surfacesof the lid piercing means without deforming until the bottom in betweenthe tops is reached. Any deformation of the exit filter 36 is thusrelatively limited. Hence, the exit filter 36 is adapted to the lidpiercing means 128 such that the capsule 2, in use, is not pierced bythe lid piercing means 128 and the lid 16 stays intact. More in generalit applies that the exit filter 36 and the lid piercing means 128 areadapted to each other such that the capsule 2, in use, is not pierced bythe lid piercing means 128 and the lid 16 stays intact.

In the example of FIG. 1, the lid piercing means 128 are shown havingsharp toothed points intended for piercing the lid. It will beappreciated that, alternatively, the lid piercing means 128 may haveblunt piercing surfaces, e.g. as indicated with dashed lines in FIG. 1.In such embodiment, an alternative capsule may, nevertheless, be piercedby the blunt piercing means 128, e.g. when the lid of the prior artcapsule consists of a sheet of aluminium foil. Parameters of the exitfilter 36 of the capsule 2 of the system 1 according to the inventioncan be chosen such that the exit filter 36 has the sufficiently hightear strength and/or forms the sufficiently low flow resistance not tobe pierced or torn. It will be appreciated that when the lid piercingmeans 128 are blunt, the parameters of the exit filter 36 may be chosento suit these blunt piercing means 128. When the piercing means 128 areblunt, the exit filter 36 may e.g. be thinner than when the lid piercingmeans are sharp, while guaranteeing that the exit filter 36 has thesufficiently high tear strength and/or sufficient stiffness and/orforming the sufficiently low flow resistance not to be pierced and/ortorn and/or ruptured.

It is possible that the lid piercing means 128 comprise ridges againstwhich the lid, in use, abuts. Such ridges may be formed by the bluntpiercing means 128 as shown with dashed lines in FIG. 1. The ridges maye.g. form at least 10%, possibly at least 25% of the portion of thesurface of the receptacle 106 which, in use, coincides with the portionof the surface area of the lid 16 overlying the second, open, end 18.Hence, in use, the lid 16 may be supported by the ridges over, e.g. atleast 10%, preferably at least 25%, of the portion the surface area ofthe lid 16 overlying the second, open, end 18. As already indicated, thelid of an alternative prior art capsule may be pierced by such ridges,whereas parameters of the exit filter 36 of the capsule 2 of the system1 according to the invention may easily be chosen such that the exitfilter has the sufficiently high tear strength and/or forms thesufficiently low flow resistance not to be pierced or torn. It will beappreciated that when the lid piercing means comprise ridges, theparameters of the exit filter 36 may be chosen to suit such lid piercingmeans.

In the example of FIG. 1, the ridges comprise edges which are not sharp.In this example a radius of curvature of the edges is approximately 50μm, although other radii are conceivable, such as 100, 200 or 500 μm.The prior art capsule may, nevertheless, be pierced by the bluntpiercing means 128, e.g. when the lid of the prior art capsule consistsof a sheet of aluminium foil. It will be appreciated that when the lidpiercing means comprise non-sharp edges, the parameters of the exitfilter 36 may be chosen to suit such lid piercing means. Parameters oflayers of the exit filter 36 of the capsule 2 of the system according tothe invention can be chosen such that the exit filter 36 has thesufficiently high tear strength and/or forming the sufficiently low flowresistance not to be pierced or torn.

It is also possible that the ridges of the lid piercing means 128 have aconvex top against which the lid 16 abuts. Hence, when the lid, in use,is pressed against the ridges, the surface area over which the lid issupported by the ridges increases, thus reducing the local pressureexerted on the lid by the ridges. Thus it is possible to provide, in aneasy manner, that the lid, in use, does not tear and/or rupture andstays intact.

In the example of FIG. 1 the exit filter 36, forming an exit area of thecapsule 2, through which the beverage, here coffee, can drain from thecapsule, is formed by a porous sheet, such as filter paper comprisingtwo layers bonded to each other, as shown e.g. in FIG. 2 and FIG. 3. Inthis example the entire lid 16 is formed as the exit filter 36. In theexamples of FIG. 1, FIG. 2, FIG. 3 and FIG. 4, the capsule 2 comprisesan outwardly extending rim 38 at the second end 18, wherein the lid 16is attached to the outwardly extending rim 38, e.g. by gluing, weldingor the like. Hence, in this example the exit filter 36, i.e. themulti-layer sheet, is attached to the outwardly extending rim 38.

In this example the exit filter 36 forms a substantially continuousfluid-permeable multi-layer sheet spanning substantially the entiresecond, open end 18 of the capsule 2. Thus, the fluid can drain from thecapsule 2 over a large area. Hence, a very homogeneous drain of beveragefrom the extractable product is obtained.

In general, parameters of the layers of the exit filter of the capsule 2of the system 1 according to the invention can be chosen such that theexit filter does not tear or rupture, e.g. having the sufficiently hightear strength and/or having sufficiently high stiffness and/or formingthe sufficiently low flow resistance not to be pierced or torn. When theexit filter 36 is e.g. made of layers of filtering paper, parameters ofthe filtering paper, such as density, thickness and/or PE-content, caneasily be chosen to provide the exit filter having the sufficiently hightear strength and/or sufficiently high stiffness and/or forming thesufficiently low flow resistance. Alternatively, when the layers of theexit filter 36 are e.g. formed by a polymeric film provided with aplurality of exit openings, parameters of the polymeric foil, such asdensity, thickness, number of exit openings, size and/or shape of exitopenings, can easily be chosen to provide the third wall having thesufficiently high tear strength and/or forming the sufficiently low flowresistance.

Different materials may be used for the different layers. Many materialsmay be suitable, for example, PE, PP, PET, nylon, EVOH, EVA, L-LDPE,LDPE, metal. Also, the layers may have a different thickness. Forexample, the thickness of a layer may be between approximately 5 μm andapproximately 40 μm. Preferably, the thickness of the layers is betweenapproximately 10 μm and approximately 35 μm. For example, the thicknessof the first layer can be approximately 12 μm or approximately 23 μm,the thickness of the second layer can be approximately 30 μm.

FIG. 2 shows an embodiment of a capsule 2 according to the invention.The exit filter 36 comprises two layers 51, 52. The two layers 51, 52are bonded together so they can act on each other and/or strengthen eachother. A physical and/or a chemical bond may be provided overapproximately entire surface of the layers. According to the invention,a first layer 51 has a higher tear strength than a second layer 52, andthe second layer 52 has a higher stiffness than the first layer 51. Thestiffness and the tear strength of the layers 51, 52 is such that thelayers will not tear, rupture or deform too much such that the exitfilter 36 may have a relatively constant flow resistance for a pressurebuilt up in the capsule, which may thus become more reproducible and/ormore controllable. In FIG. 2 is shown that the exit filter 36 comprisesa porous layer 51 and a perforate layer 52 with openings 30. FIG. 3shows an embodiment of a capsule of which the exit filter 36 has aperforate layer 51 and a porous layer 52. The porous layer may besufficiently strong to prevent widening of the openings 30 of theperforate layer, and the perforate layer may be sufficiently stiff toprevent tearing of the porous layer. Also, as can be seen in FIG. 4, twoperforate layers may be provided or two porous layers may be provided.The perforations 30 of the layers 51 and 52 of the exit filter 36correspond with each other, as to provide fluid passages for dischargingthe fluid from the capsule 2. Also a multi-layer filter may be providedcomprising more than two layers. For example a multi-layer filtercomprising three or more layers may be provided, each of a differenttear strength and/or stiffness. By providing different layers of eachdifferent characteristic, the layers may strengthen each otherscharacteristics thus providing a multi-layer filter that may not tear,rupture or being pierced. Preferably, for a perforate layer theperforations may not deform under influence of pressure. Preferably, thedimensions of the perforations may vary less than 3% during use of thecapsule during preparation of the beverage. Also, for a porous layer,preferably the pores may not deform and the dimensions of the pores maynot vary more than 3% during use of the capsule during preparation ofthe beverage.

The exit filter 36 may be provided upstream or downstream of the lid 16,or may be provided in the exit opening of the lid 16. Preferably theexit filter 36 is attached to the outwardly extending rim 38. The exitfilter 36 may also be attached to the circumferential wall 14.

In general, the exit openings 30, perforations of a perforate layer orpores of a porous layer, are dimensioned such that a dimension of theopening 30 is sufficiently small to retain most of the larger particlesof the extractable product, such as ground coffee, inside the capsule 2.Only very small particles, so-called fines, may exit via the openings.Also, in general, the exit openings 30 are dimensioned and distributedsuch that a sufficient flow resistance may be obtained in order to allowa certain pressure built up in the capsule before the extracted beveragedrains from the capsule.

According to an aspect of the invention, the bottom 12 is provided withan entrance filter 34. The entrance filter 34 may be provided as amulti-layer filter comprising for example two layers 61, 62, as shown inFIG. 2 and FIG. 3. Also, an entrance filter comprising more than twolayers may be provided. Alternatively, a capsule 2 may also be providedwithout entrance filter 34, leaving the entrance area open. The entrancefilter 34 may be provided upstream or downstream of the bottom 12,or—not shown—may be provided in the entrance opening, attached to aninwardly extending rim 42. Since the rim thickness is not present in theinner space 20 of the capsule 2, the internal volume may thus bemaximised. The entrance filter may alternatively or additionally beattached to the circumferential wall 10.

A first layer 61 of the entrance filter 34 may be a porous sheet, e.g.filter paper, and a second layer 62 may be a perforate sheet, e.g.polymeric foil, as shown in FIG. 2 and FIG. 3. According to an aspect ofthe invention, the first layer has a higher tear strength and the secondlayer has a higher stiffness. Alternatively, the first layer may be aperforate foil and the second layer may be a porous sheet. Entranceopenings 24 may be distributed approximately evenly over the entrancearea as to allow a homogeneous supply of the fluid to the extractableproduct. As shown in FIG. 4, both layers 61 and 62 of the multi-layerentrance filter 34 may be perforate layers. The perforations 24 in bothlayers correspond with each other as to provide fluid passages.

It shall be obvious that the invention is not limited in any way to theembodiments that are represented in the description and the drawings.Many variations and combinations are possible within the framework ofthe invention as outlined by the claims. For example, the embodimentsdescribed show the first layer upstream of the second layer. It may beclear to the person skilled in the art that the second layer may also beupstream of the first layer. Also, in the embodiments described, thefirst layer may be thinner than the second layer. It may be clear to theperson skilled in the art that the second layer may also be thinner thanthe first layer. Combinations of one or more aspects of the embodimentsor combinations of different embodiments are possible within theframework of the invention. All comparable variations are understood tofall within the framework of the invention as outlined by the claims.

What is claimed is:
 1. A system for preparing a predetermined quantityof beverage suitable for consumption using an extractable product,comprising: an exchangeable capsule, and an apparatus comprising a fluiddispensing device for supplying an amount of a fluid, such as water,under pressure to the exchangeable capsule, and a receptacle for holdingthe exchangeable capsule, wherein the exchangeable capsule comprises acircumferential wall, a bottom, and a lid enclosing an inner spacecomprising the extractable product, wherein the fluid dispensing deviceis arranged for supplying the fluid to the extractable product throughthe bottom for forming the beverage, wherein the bottom comprises anentrance area and the system is arranged for bringing the fluiddispensing device in fluid connection with the entrance area forsupplying the fluid to the extractable product for preparing thebeverage, wherein the lid comprises an exit area and the systemcomprises an outlet which, in use, is in fluid communication with theexit area for draining the prepared beverage from the capsule andsupplying the beverage to a container such as a cup, wherein thereceptacle is arranged for draining the prepared beverage from thecapsule through the exit area, wherein the exit area of the capsulecomprises a sheet-shaped multi-layer filter comprising at least a firstlayer and a second layer bonded together, wherein the first layer has ahigher tear strength than the second layer and wherein the second layerhas a higher stiffness than the first layer.
 2. The system of claim 1,wherein the first layer has a tear strength that is at least 20%,preferably 50% higher than the tear strength of the second layer andwherein the second layer has a stiffness that is at least 20%,preferably 50% higher than the stiffness of the first layer.
 3. Thesystem of claim 1, wherein the first layer comprises a first materialhaving a higher tear strength than the second layer and the second layercomprises a second material having a higher stiffness than the firstlayer.
 4. The system of claim 1, wherein the first layer is perforateand/or porous and/or wherein the second layer is perforate and/orporous.
 5. The system of claim 4, wherein the first layer and the secondlayer are perforate wherein the perforations of the first layercorrespond with the perforations of the second layer.
 6. The system ofclaim 1, wherein the first and/or the second layer comprisespolypropylene and/or polyethylene and/or polyethylene therephthalateand/or chlorinated polypropylene and/or nylon and/or ethylene vinylalcohol and/or ethylene vinyl acetate and/or low density poly ethyleneand/or metal.
 7. The system of claim 1, wherein the multi-layer filteris formed by: a porous sheet, such as filtering paper, and/or a foil,such as a polymeric film, provided with a plurality of entranceopenings.
 8. The system of claim 1, wherein the entrance area comprisesa sheet-shaped filter.
 9. The system of claim 8, wherein the entrancearea comprises a multi-layer filter.
 10. The system of claim 9, whereinthe multi-layer filter comprises a first layer and a second layer,wherein the first layer has a higher tear strength than the second layerand wherein the second layer has a higher stiffness than the firstlayer, wherein the first and the second layer are bonded together. 11.The system of claim 1, wherein the multi-layer filter comprises at leastone layer with openings, wherein the openings are distributed oversubstantially the entire surface of the filter layer.
 12. The system ofclaim 11, wherein the openings have a diameter of approximately 0.2 mmto approximately 0.4 mm.
 13. The system of claim 1, wherein thethickness of the first and/or the second layer is between approximately5 μm and approximately 40 μm, preferably between approximately 10 μm andapproximately 35 μm.
 14. The system of claim 1, wherein the first layeris thinner than the second layer.
 15. The system of claim 1, wherein thelid closes the capsule at an outer end.
 16. The system of claim 1,wherein the circumferential wall is substantially rigid.
 17. The systemof claim 1, wherein the receptacle comprises bottom piercing meansintended for piercing the bottom of an alternative capsule for creatingat least one entrance opening for supplying the fluid to the extractableproduct through said at least one entrance opening, and wherein thebottom of the capsule of the system comprises an entrance filter forsupplying the fluid to the extractable product there through, whichentrance filter is, in use, positioned at a distance from the bottompiercing means, such that the capsule of the system is not pierced bythe bottom piercing means and the bottom stays intact.
 18. The system ofclaim 1, wherein the receptacle comprises bottom piercing means intendedfor piercing the bottom of an alternative capsule for creating at leastone entrance opening for supplying the fluid to the extractable productthrough said at least one entrance opening, and wherein the bottom ofthe capsule of the system comprises an entrance filter for supplying thefluid to the extractable product there through, which entrance filter isa multi-layer filter of which the first layer has a sufficient tearstrength and the second layer has a sufficient stiffness such that thecapsule of the system, in use, is not pierced by the bottom piercingmeans and the bottom stays intact.
 19. The system of claim 1, whereinthe receptacle comprises lid piercing means intended for piercing theexit filter of an alternative capsule when the exit area sufficientlypresses against the lid piercing means under the influence of thepressure of the fluid and/or beverage in the capsule for creating atleast one exit opening through which the beverage can drain from thealternative capsule, and wherein the exit area of the capsule of thesystem comprises a multi-layer exit filter, through which the beveragecan drain from the capsule of the system, of which the first layer has asufficient tear strength and the second layer has a sufficient stiffnesssuch that the capsule of the system, in use, is not pierced by the lidpiercing means and the lid stays intact.
 20. A capsule of the systemaccording to claim
 1. 21. Use of a capsule for preparing a beverageusing an apparatus of a system according to claim
 1. 22. A method forpreparing a predetermined quantity of beverage suitable for consumptionusing an extractable product, comprising: providing an exchangeablecapsule, comprising a circumferential wall, a bottom, and a lidenclosing an inner space comprising the extractable product, providingan apparatus comprising a receptacle for holding the exchangeablecapsule, a fluid dispensing device for supplying an amount of a fluid,such as water, under pressure to the exchangeable capsule for preparingthe beverage, and an outlet which, in use, is in fluid communicationwith the capsule for draining the prepared beverage from the capsule andsupplying the beverage to a container such as a cup, supplying the fluidto the extractable product for preparing the beverage, wherein the lidof the capsule is a sheet-shaped multi-layer filter comprising at leasta first layer and a second layer bonded together, wherein the firstlayer has a higher tear strength than the second layer and wherein thesecond layer has a higher stiffness than the first layer.